Rheostat.



C. D. KESTNBR.

BHEOSTAT.

APPLIOATION FILED DEO. 31, 1909.

Patend Jan. 10, 1911.

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C. D. KES/INEE.

RHBOSTAT.

LPPLIOATIOH Hmm 1120.31, v1909.

Patented Jani 10, 1911.

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- UNITED sTAriis PATENT OFFICE.

D. XESTNEB., NEW YORK, N. Y., ASSXGNOR TOTHE NtEYROWITZ MANU- FACTURINGCO., A CORPR-ATION 0E NEW JERSEY. l

imnos'ran Specification of Letters Patent.

Patented Jan. 1o, 1911.

Application filed December 31, 1909. Serial No. 535,812.

To'all whom 'it may comern: p .uated for a considerable range, sincehere Be it known that I, CHARLES D. Kns'rnnii, the graduations atone endare undesirably a citizen. of the United States, residing in close whileat the other, unnecessarily large. the .city 0f New York, in the boroughof and to overcome this objectionable.feat-ureA 5 Manhattan and-State ofNew York. have inthe present invention has been evolved, einm es:

vented certain new and useful improve# bod ing a new form ot' rheostatwhich adments in Rheostats, of which the following un ,ably adaptslitself to the required condiis a full, clear, and exact description`tions. liurther,l the device considered as a This invention relates to alamp rheostat, whole and even more especiallyl the novel and has for itsobject theproduction ei' a rlicostat herein y.presented is admirably 35,

compact device. adapted to'be inserted in a adapted to various otheruses. lamp or other electric circuit for the purpose The following is adescription of one emof regulating the resistance tl'ierein' andbodimentcf my invention, 'which .is illusmore especially to provide adevice in which trated in the accompanying drawings, like ,15 saidresistance may be varied by some conparts being designated by likereference 7o venient means, such for example as a knob characters. orhandle, `and securing thereto a pointer lReferring to `said drawings,Figure l is adapted to cooperate with a scale, the gradua frontelevation of a socketed lamp rheoations of which should referably besubstat. Fig. f2 is a vertical section taken on l0 tantiallv equallyspaced? This arrangethe median line of Fig. l. Fig. 3 is a front 75 mentis or'special utility in connection with elevation, partly in section,of the device tungsten lampsand more particularly those with the scaleor front plate and arbor 'rc- 'ofllow voltage. These lamps, the bulbs ofmoved. Fig. e is a rear elevation with the which may be very small, areused in conback plate removed. Fig. 5 is a perspective nection withvarious surgical appliances to view of said back plate. Fig. 6 is a.view of 8G illuminate the mouth or. nasal cavities er fthe arbor showingthe insulating member likev parts', and -it becomes necessarytretherein. Fig. 7 is the rheostat proper; quently to vary the size ofthe bplb and shown partly in section. Fig. 8 is a vertical consequentlythe voltage ofthe lamp to fit section of the top socket-stein base,andcon- M 'the cavity or the instrument. When, for necting parts. 'Fig 9is a modification of 85 example,l a six volt lamp is used, it is foundthe rheostat proper. necessary to .insert a given Iresist-ance into Inthe drawings, l designates a cylindrical A the ordinary lamp circuit toaccommodate casing, preferably of sheet metal, having j a lamp of thislow voltage. Upon a subsedisposed on opposite sides thereof male and '85quent change to, kfor example, a lamp of female socketconnectionsrespectively 2 and 90 A twelve volts, the relative travel of the mov- 3.These socket portions are carried upon able element in a rheostat of theusual type bosses or extensions 4c formed byl soldering .will not `beproportional to the change in annular members into apertures of saidcas-4 voltage of' the lamp, and were afscale to be ing, and insulatingbase kmembers are seated 40 *used in connection with the aforesaid rcinsaid extensions. The upper insulator 5, 95

sistance, as an indicating means ot the is formed with verticallydisposed recesses amount thereof in circuit, the fnfaduations adapted toreceive conductive sleeves 6, and, upon said scalf, would be unequallyspaced i the lugs 7 of a vthreaded conductive shell 8. so that at one"ad thereof the division lines lions 9 and l0 extend through apertures'in 3F would be spaced. far apart, while at the other said .lues andthrough the lower portion of 1Go end they would be disproportiomitclyclose the i` lating base, and are respectively together. For conveniencein use therefore, g .flidly into the liber strips lll-419.. it isdesirable that some means be provided i (j ps if; and M, preferably ot'brass, are A whereby when for example the required i'oltimlcpentlentlysecured to strips l1 and 1:2, age is-to be doubled trebled or quadrupledbeing positioned one on either side of the the handle and pointer shallpreferably travcenter line of the base; the bolt 9 contacting ersedistances proportional to the voltage re with clip i3. The fiber stripsservelto space quired, thereby permitting of less care in the clips'foin a conductive bar lo, united the adjustment of the rheostat.Partitur to the insulating base by a riveted extension upon metallicthrough-bolt 16, the head 17 1X0 l5 larly is this the case where thescale is grad of which is positioned onthe top of the base and togetherwith the threaded shell aforesaid, forms the male socket connections.The lower insulating base 18 carries upon the lower portion thereof athreaded shell 19, said shell being secured to said socket by screws 20,21. Said screws extend upward from the base and through a fiber block22; screw 20 threading into a nut 23, and screw 21 threadin .into ametal bar 24. Said bar may be furt 1er secured to the liber block 22 byscrews 25 if desired. Extending upward through the base 18 is a contactscrew 26 threaded into a. bar 27. The fiber block 22 being recessed forthe reception of said bar. 'lransversely positioned in said casing isthe rheostat proper, in this instance formed by winding a coil ofconductive material 29, preferably German silver wire, upon aninsulating core or base 28, in this instance of fiber, having` theV formsubstantially of a truncated conc.- The various turns of the coil aresubstantially insulated from each other by a coating of lacquer, orother insulating medium, and the said core and coils positionedthereupon are in this instance shownv flattened, as at 30, along oneside thereof, the insulating coating being scraped from the exposedsurfaces of the coil along this flattened portion. The core 28 tapersgradually from the end 31, which is secured to the casing by screw B2,and the opposite or reduced extremity of said core is flanged as at 33to better retain the wire wrapping, said end in turn being secured tothe casing by a'screw 34. This exem lification of my rheostat is merelyone o many possible diverse forms thereof, and should the exigencies ofthe case require a structure of other shape than that of a truncatedcone, as for example that shown in Fig. 9 such structure would beconsidered within the purview of my invention.

One modification of my rheostat is illustrated in Fig. 9, wherein thecore is omitted, the wire forming the rheostat being of sufficientrigidity to permit dispensing with the said core. The metallic parts 35in this form of device may be supported by loops 36 adapted to beengaged by screws or like means secured to the walls of the casing; thecoil vbeing of course properly insulated by strips of mica or the like.

Positioned on the front of casing 1 is a tace plate 37, secured inposition upon the casing by lugs 38. Said plate carries upon the outerface thereof a scale A pointer 40 carried upon a sleeve 41 cooperateswith said scale. An arbor 42 having a reduced portion 43 adapted to beseated in an aperture 44 in said face plate, carries the sleeve 41 uponan extension 45 thereof; a knurled nut 46, preferably of insulatingmaterial, clamping said sleeve firmly in position upon the arbor andthereby securing said arbor in its bearing. The rear end of the arbor isrecessed for the reception of an insulating fiber block 47, and saidblock carries in the slotted extremity 48 thereof a resilient conductivefinger 49, preferably of rolled copper or like material. The upperextremity 50 of said finger is dished for reasons hereinafter set forth,and said finger is secured to said block by a screw 51.

A perforated rear or back plate 52 formed or provided with a stiffeningflange 53 preferably soldered thereto, completes the casingl proper;said .plate being secured to the casing by struck-up lugs 54, similar tothose on the front plate. These lugs may be threaded for the receptionof securing screws -55. The resilient strip 56 is secured by a screw 57to the bar 24, and extends obliquely upward therefrou'rtoward the innerextremity of arbor 42. The end of said strip is cupped at 58 to engage aconsiderable surface of screw 5l carried by the said arbor. Theconnections of the several arts above described can be best explainewhile describing the course of current through the apparatus. Assumingthat the socket stem 2 has been screwed into` position in the usual lampsocket, current will enter let us say, at 17, passing thence downthrough conductor 16 to bar 15. A wire 59 connects said bar with bar 27,current thence proceeding throu h contact screw 26 to the center contacto a lamp; returning from the lam) through shell 19, screw 21, bar 24,the resilient member 56, screw 51 into finger 49; then according to theosition of said finger upon the rheostat coi through a greater or lessextent of said coil to a lead 60 extendin therefrom to the L-shaped bar13, and rom thence through screw 9 and sleeve 6, back to the shell 8,completing the circuit.

Ventilating holes 61 provided in the walls of the casing, together withthe perforated back plate afford a sufiicient circulation of air toprevent the device from becoming overheated when in use. As a matter ofprecaution to avoid any possibility of shortcircuiting, a layer of mica62 is provided between the arbor and conductive bar 27.

To afford a finished appearance to the exterior of the bottom socketmember7 a metallic sleeve or ring 63 is placed in position thereupon,engaging the flange 64 of the insulating base, and being. secured inposition by a knurled nut 65.

As it may not always be desirable or possible to use my device' inconnection with a lamp socket, l have provided threaded binding posts66, 67, upon the face thereof. Said posts are insulated from the faceplate by washers 68; post 66 being screwed into the short leg ofL-shaped clip 13, while ost 67 is correspondingly screwed into c ip, 14.This latter bar is not in electrical connection with the shell of thesocket stem, since the wise.

lead Wires/69 connect the ends of bai 14 withbar 24 and screw 57,therebyplacing blnding post- 67 in electrical connection with finger49.Bar 13 is connected by lead GO with the rheostat coil in a manneralready' described, and hence the circuit is adapted to be completedbetween said binding posts,

through the medium of said rheostat.

` The operationof the rheostat proper is obvious` and it may be merelyadded that it is possible by varying the sizes of the vari ous turns ofthe coil to effect any predeter mined changes of resistance desiredWhile :permitting the scale used in connection therewith to be graduatedevenly or otheru It will be noted also that the rheostat 1s adapted tooperate as a switch, since if .the revoluble arm 49 be rotated to theex- .throw of said arm, and the end of saidV arm 1s dished ashereinbefore mentioned to bet.-

ter permit a sharp line contact with the respective turns of theresistance coll.

"The .equal .spacing of thescale obviates the. objections to the use ofan unevenly.

raduated one, to wit the difliculty of reading and, interpolatinwhen thelines of the scale are `most close y spacedv and the liability of theoperator to turn the controlling knob to an' improper position for agiven lamp, which may cause the burning out-thereof; the interpolationabovereferred to being in such case necessitated by' the fast that whenthe graduations are close the4 designating numerals or marks cannot allbe applied, since such figures would be too small, and interpolation.must be re sorted to, with the consequent liability of erroneouslyadjusting the rheostat.

' What. I clan is:-

l. In a rheostat, a tapering insulating.

core, a conductive member wound thereon,

ter-iai, hav-ing 'the turns thereof of unequal size, and a. memberadapted'to contact with various turns of said coil when iela'tlvemovement occurs between sa-idcoil and said member.

A rheostatcomprising a rigid tapered coil of coi'nluctive material incombination with a contact adapted to malte successive connection ywiththe turns thereof.

et. A rheostat coniprisinga rigid coil. having the 'turns thereof ofvarying size and aninsulating base' therefor in combination with aContact adapted to malte successive connectionwith the turns thereof.

A rheostat comprising a tapered coil, iatteued upon one side, arevoluble arbor disposed substantially at right angles to the axis ofsaid coil, and an arm carried by said arbor and having a protuberanceadapted to resilientiy engage Avarious portions of said flattenedportion. l

(i. A lamp rheostat comprising a scale, a coil having the various turnsthereof of differing` si'ze,p a revoluble member carrying an arm and apointer, said arm being adapted to engage Various turns of said coil,and

said pointer indicating'upon said scale when the arm is in properposition foruse with a given lamp.

7. A- lamp rheostat coi'nprising a casing having means forconnecting-said rhe'ostat in circuit/with a` lamp, a nonconductive corehaving the shape substantially of a truncatedcone secured to a. side ofsaid casing, a resistance wire wound thereupon, and-means for engagingthe turns of said coil for adapting the current to the lamp to beused'.v r

S. A rheost-at comprising a non-conductive base the successivevtransverse sections of which are of varying areas, a coiled con ductivemember mounted upon and con forming to the Variations of the base, andan arm adapted for engagement with the turns of said member.

In witness whereof, I subscribe my signature.y in the presence of twowitnesses.

Louis Pn. Garen.'

